The carbon cycle: Environmental concerns

1. Fossil fuels (oil, coal, and natural gas) supply about 80% of the energy used by industrialized countries.

2. Supplies are running out!

3. Use and acquisition of fossil fuels damage the environment via pollution (air & water), mining, oil drilling, ore and oil processing, refining, and shipping accidents.

4. Global warming is attributed to increased carbon dioxide in the atmosphere -- directly related to consumption of fossil fuels.

5. Political instability and insecurity result from scarcity -- the Gulf War is an example.

What can be done?

1. Conservation: Turn the thermostat down in winter and up in summer; car pool; tune up the engine; replace old appliances and cars with new ones; ride the bus; use a bike; rollerblade; skateboard; walk.

2. Find alternative energy sources: Renewable biomass; solar; wind; nuclear (?); fusion (?).

More on Ecological Footprints

In general, individuals with more income have larger EF's than do individuals with less income

Not fixed by income alone, but depends greatly on patterns of spending

Some ways to reduce individual EF's

Multi-unit housing close to work and shopping vs single unit housing in the 'burbs

Small, fuel-efficient car vs standard model

Changes in food consumption

Less animal-based products

Less processed and packaged foods

Purchase high-quality and durable goods

Switch to renewable energy sources

Heating a given amount of water using solar-thermal collectors produces an EF 100X smaller than heating the same amount using fossil fuels

Ecological Footprint of different ways to commute 5 km to work

Bicycle -- requires an additional 122 square meters of land (extra food production)

Bus -- requires an additional 301 square meters of land (carbon sequestration)

Car (single occupant) -- requires an additional 1,442 square meters of land (carbon sequestration)

Water: Do we
have enough?

Ice & Snow2.07%
Lakes & Reservoirs0.009%
Saline Lakes0.007%
Soil Moisture0.005%

Fresh Water: Where is it distributed?

1. South America and Asia have about 1/2 of the total global runoff of fresh water.

2. South America's 27% of global runoff shared by about 6% of total population on earth; most of the runoff occurs in habitats inhospitable to humans.

3. Asia's freshwater runoff occurs in areas suitable for agriculture; Asia has 60% of the global human population.

4. Iceland is the richest country in the world when it comes to water: An annual renewable supply of 177 million gallons per person (68X the per capita supply in the USA; 20,000X the per capita rate of Egypt).

5. Kuwait and Bahrain have NO renewable water supply. The entire freshwater supply comes from desalination of sea water.

How much water is used each year?

1. 10% of annual runoff used globally each year; 25% of standing water used each year.

2. 1400 gal per person per day used in the USA; about 1/5 of the annual runoff.

3. Industry accounts for 1/4 of all water use globally. In low income societies, agriculture accounts for most water use.

4. One third of the world's population lacks safe drinking water or adequate sanitation.

5. WHO estimates that about 40 countries lack enough good water per person per year for maintaining a healthy life.

Return to PB 102 Class Notes Homepage
Please send your suggestions, comments, corrections, and/or questions to
Last updated February 1, 1999.